passt: Fix build with gcc 7, use std=c99, enable some more Clang checkers

Unions and structs, you all have names now.

Take the chance to enable bugprone-reserved-identifier,
cert-dcl37-c, and cert-dcl51-cpp checkers in clang-tidy.

Provide a ffsl() weak declaration using gcc built-in.

Start reordering includes, but that's not enough for the
llvm-include-order checker yet.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/igmp.c b/igmp.c
index 8f6b263..2f3a9d1 100644
--- a/igmp.c
+++ b/igmp.c
@@ -13,4 +13,4 @@
  */
 
 /* TO BE IMPLEMENTED */
-__attribute__((__unused__)) static void __(void) { }
+__attribute__((__unused__)) static void unused(void) { }